Browsing by Author "Macdonald, DW"

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    Adrenocorticotrophin-induced stress response in captive vicunas (Vicugna vicugna) in the Andes of Chile
    (UNIV FEDERATION ANIMAL WELFARE, 2003) Bonacic, C; Macdonald, DW; Villouta, G
    The vicuna is mainly used in two ways: wild captured, shorn and returned to the wild; or wild captured and maintained in captivity as part of a programme of sustainable use in the Andes of South America. Farming of wild vicunas has hitherto involved no assessment of their welfare. In this study we measured a set of basic blood parameters in order to characterise baseline values in captivity, and we then characterised adrenal cortical responsiveness using an ACTH challenge. The ACTH challenge is widely used for assessing neuroendocrine responses to stress and is now increasingly being applied to studies of wild animals' welfare. Five male vicunas were injected with exogenous ACTH and their responses compared with those of a control group injected with placebo. Behavioural and haematological changes were monitored. Injection of ACTH produced a 4.5-fold increase in cortisol concentration within 1 h. Total white blood cell count almost doubled in less than 5 h. The neutrophil:lymphocyte ratio also changed, with a decrease in lymphocytes and an increase in neutrophils, suggesting that the neutrophil:lymphocyte ratio was affected by the ACTH challenge. Packed cell volume increased from 40% to 44%. Observations of individual vicunas during sampling revealed no discernible behavioural differences between treated and control animals; however, animals that had higher initial baseline cortisol concentration made more attempts to escape, and vocalised more during handling, regardless of whether they were treated with ACTH or placebo. The results reveal the different blood parameter levels associated with stress in different species and highlight the hazard of interpreting stress levels in one species on the basis of measures calibrated in another. We provide calibrated reference values for future studies of stress in vicunas.
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    Density dependence in the camelid Vicugna vicugna: the recovery of a protected population in Chile
    (CAMBRIDGE UNIV PRESS, 2002) Bonacic, C; Macdonald, DW; Galaz, J; Sibly, RM
    The vicuna Vicugiia vicugna is a wild South American camelid. Following over-exploitation, which brought the species to the brink of extinction in Chile in the 1960s, the population was protected. Since 1975 the population has been censused annually, generating one of the most extensive long-term census databases for any South American mammal. In this paper we use these data, and measures of environmental parameters, to describe the population growth trend of the species and to estimate carrying capacity. Our results indicate that the vicuna has been protected successfully in northern Chile. The census data reveal that, following protection, the population displayed logistic growth between 1975 and 1992. Population growth rate declined linearly with population size, which indicates a degree of density dependence. Density independent factors, such as rainfall, may also have been important. The principal density dependent effect observed was that birth rate declined in those family groups with the most breeding females. The carrying capacity of the study area was estimated from the census data and from models based on precipitation and local primary productivity. Using the census data, an estimation of carrying capacity as the asymptote of the fitted logistic curve suggested that the vicuna population should reach approximately 26,000 vicunas, whereas estimation when the population growth rate was equated to zero gave a carrying capacity of c, 22,000. Coe's method based on local precipitation predicted 31,000 vicuna, whereas Lavenroth's method based on local primary productivity predicted 26,000 vicuna. In reality, the census data showed that the population peaked at 22,463 vicunas in 1990. The results are discussed in relation to the need for better census techniques and the implications of density dependent effects for the management of the vicuna in Chile.
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    The effect of transport on cortisol, glucose, heart rate, leukocytes and body weight in captive-reared guanacos (Lama guanicoe)
    (UNIV FEDERATION ANIMAL WELFARE, 2004) Zapata, B; Gimpel, J; Bonacic, C; Gonzalez, B; Riveros, J; Ramirez, A; Bas, F; Macdonald, DW
    Current procedures for ranching and sustainable use of guanacos necessitate their transport. Transportation is a risky process for animals, and is a particular concern for wild-caught or semi-domesticated species such as the guanaco - a wild South American comelid species increasingly being established on forms in Chile and Argentina. This study investigated the effect of transport on the physiological and behavioural responses of eight castrated adult male guanocos, transported on a single 2 h journey at a stocking density of 113.5 kg m(-2) (0.76 m(2) per animal). Plasma cortisol and blood glucose concentration, total and differential white blood cell (WBC) counts, heart rate, and body weight were measured one week before, immediately before, immediately after, 2 h after and one week after transport. Behavioural responses were recorded during handling prior to loading. Immediately after transport we found significant increases in plasma cortisol concentrations and neutrophil. lymphocyte (N:L) ratio, the latter peaking 2 h after transport. Heart rate increased significantly only during loading, while body weight remained constant throughout. Behavioural responses related to handling (Jumping, vocalising, kicking, spitting and urinating) were not associated with the physiological response. All variables returned to pre-transport values within one week. Transport of guanacos under these conditions produced physiological changes similar to those associated with a mild and transient stress response in other species and which, we judge, fall comfortably within acceptable limits for their welfare.
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    The physiological impact of wool-harvesting procedures in vicunas (Vicugna vicugna)
    (UNIV FEDERATION ANIMAL WELFARE, 2003) Bonacic, C; Macdonald, DW
    A current programme of wildlife utilisation in the Andean region involves the capture of wild vicunas, their shearing, transport and, in some cases, captive farming. The effects of these interventions on the physiology, and thus welfare, of wild vicunas are unknown. As a first step to quantifying and thus mitigating any adverse welfare consequences of this harvest, we measured the immediate and longer-term physical and physiological effects of capture, shearing and transport. A sample of juvenile male vicunas was captured Six were shorn at the capture site, six after two weeks in captivity, and the remaining seven animals were kept as controls for 39 days. In general, vicunas showed changes in blood glucose, packed cell volume, cortisol, and neutrophil: lymphocyte ratios within 4-6 h following capture. Creatine kinase was also affected by capture and transport, showing a peak plasma level 24 It after capture, which was followed by a peak plasma level of aspartate aminotransferase four days after capture and transport. After 12 days in captivity, all of the vicunas showed physiological parameters close to expected baseline values for the species. We could detect no differences it? physiological parameters between animals that were captured, sheared and transported and those that were only captured and transported. Similarly, we could detect no differences in most responses of vicunas between those sheared after 12 days, in captivity and a control group held under similar conditions but from which blood was sampled without shearing. A further comparison between animals sheared immediately after capture and animals sheared after 12 days in captivity revealed that creatine kinase levels were higher in the former group. During transport prior to release back into the wild, only minor injuries (lip bleeding and limb contusions) and a significant increase in rectal temperature were observed Our results provide a basis for recommendations to improve the welfare of vicunas during the wool hat-vest, and provide baseline and stress-response data to serve as reference points for further studies of vicuna welfare.